| 摘要 |
<p>An optical waveguide 2 has a first diffractive grating region 8 arranged to receive light and diffract the received light along the optical waveguide 2, an intermediate diffraction grating 10 optically coupled to the first diffractive grating region 8 to expand received light in a first dimension and a second diffractive grating region 9 optically coupled to the intermediate diffraction grating 10 to expand light in a second dimension, orthogonal to the first dimension and to output the light expanded in the first and second dimensions from the optical waveguide 2 by diffraction. The first and second diffractive grating regions 8,9 are a common grating which is a separate item from the intermediate diffraction grating 10.</p> |
